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A119563
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Define F(n) = 2^(2^n)+1 = n-th Fermat number, M(n) = 2^n-1 = the n-th Mersenne number. Then a(n) = F(n)+M(n)-1 = 2^(2^n) + 2^n - 1.
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7
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2, 5, 19, 263, 65551, 4294967327, 18446744073709551679, 340282366920938463463374607431768211583, 115792089237316195423570985008687907853269984665640564039457584007913129640191
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OFFSET
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0,1
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COMMENTS
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The first 5 entries are primes. Are there infinitely many primes in this sequence?
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LINKS
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FORMULA
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EXAMPLE
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F(2) = 2^(2^2)+1 = 17, M(2) = 2^2-1 = 3, F(2)+ M(2) - 1 = 19
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PROG
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(PARI) fm3(n) = for(x=0, n, y=2^(2^x)+2^x-1; print1(y", "))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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